NATURAL LATEX AND SYNTHETIC LATEX

Natural rubber latex (NRL) is a milky fluid obtained from the Hevea brasiliensis tree (Rubber tree), which is widely grown in South East Asia, and other countries. In mattress industry, Natural Latex has been used since 1926 when Dunlop introduced a technology to produce vulcanized rubber latex foam due to its large stretch ratio, high resilience, and hyperelastic.

There is a whole world difference between NRL and Synthetic Rubber. Synthetic Rubber became popular in the United States during World War II. The form of synthetic latex used in our latex foam mattress toppers is Styrene-Butadiene Rubber, also known as SBR. SBR is produced with the use of petrochemicals which come from chemical labs and petroleum by-products. And NRL comes from rubber farms planted in the cultivated forests.

Cultivating Rubber trees in South East Asia

The climatic conditions for optimum growth of rubber trees are:

Rainfall of around 250 mm evenly distributed without any marked dry season and with at least 100 rainy days per year

Temperature range of about 20 to 34°C, with a monthly mean of 25 to 28°C

High atmospheric humidity of around 80%

Bright sunshine amounting to about 2000 hours per year at the rate of six hours per day throughout the year

Absence of strong winds

These climate conditions make South East Asia countries like Vietnam, Thailand, Indonesia… perfect for farming the best latex fluid in the world.

In Vietnam, lots of exhausted lands were transfromed into areas specializing in rubber trees and forestation together Sustainable Development of Rubber Tree Program has become a crucial part in cultivating and farming rubber trees in Vietnam.

The automatic irrigation system in the seeding garden in the Thuan Phu Rubber Farm.

Cross-fertilizing the sapling rubber trees

There are extensive plantations with these trees in southeast Asia; the earlier practice was to just burn the tree at the end of its latex-producing cycle. Rubberwood is advertised as an "environmentally friendly" wood, as it makes use of plantation trees that have already served a useful function.

Harvesting rubber latex fluid

The rubber trees are tapped normally in the morning, a sliver of bark is sliced at an angle, and a small amount of the fluid is collected daily. Each rubber tree can be harvested about 180 days per year, except during the rainy season and the summer. The trees will drip latex for about four hours, stopping as latex coagulates naturally on the tapping cut, thus blocking the latex tubes in the bark.The cut is about three feet long, and the latex flows for about an hour. Then the cut heals and the stops flowing. A good tapper can tap a tree every 20 seconds on a standard half-spiral system, and a common daily "task" size is between 450 and 650 trees.

When the latex is harvested which is about 2/3 water, has pure state as fairly thick, and needs to be processed.

Harvesting latex in Dau Tieng Rubber Farm

Processing

The latex will coagulate in the cups if kept for long. The latex has to be collected before coagulation. The collected latex, "field latex", is transferred into coagulation tanks for the preparation of dry rubber or transferred into air-tight containers with sieving for ammoniation. Ammoniation is necessary to preserve the latex in a colloidal state for longer periods of time.

Latex is generally processed into either latex concentrate for manufacture of dipped goods or it can be coagulated under controlled, clean conditions using formic acid. The coagulated latex can then be processed into the higher-grade, technically specified block rubbers such as SVR 3L or SVR CV or used to produce Ribbed Smoke Sheet grades.

In Dunlop technology, concentrated latex is required. To prevent coagulation from latex fluid, the time and the distance is crucial. Some factories have the advantage of the locations close to critical materials and these factors can bring the key success in manufacturing mattresses. The best state of latex liquid is ensured.